8 Most Accurate Ways to Distinguish Real Diamonds from Fakes

The answer is: Preliminary identification is possible, but absolute accuracy is not.

Some signs observable with the naked eye, such as dropping them in water, breathing on the surface, observing light refraction, etc., can help with preliminary identification, but they are not sufficient to definitively conclude whether a stone is a diamond or not.

Even gemologists often use specialized loupes, microscopes, or testing equipment for verification.

Therefore, observational methods should only be considered an initial assessment step. 

Jemmia recommends that you do not try to distinguish diamonds with the naked eye but instead visit specialized testing facilities for the most accurate check.

One of the most modern screening devices available today is the GIA iD100®. This device uses spectroscopy and luminescence analysis technology to quickly identify natural diamonds and detect cases that require further in-depth examination, such as lab-grown diamonds or certain diamond simulants.

Are you unsure if the stone you own is a natural diamond, lab-grown diamond, or a simulant?

📞 Contact us immediately at 0838 353 333 or Zalo Jemmia Diamond to have Jemmia's diamond experts assist you with free testing and consultation using specialized gemological equipment right at our store.

8 Ways to Check Real vs. Fake Diamonds with the Naked Eye

Method 1: Observe the Sparkle

Real diamonds reflect white light very strongly, creating a sharp and deep brilliance. This effect is called Brilliance.

In contrast, many imitation stones often give off a "harsh" light, lacking depth or reflecting light less effectively.

When placed side-by-side under the same light source, real diamonds usually appear sharper and more refined.

Method 2: Observe the Rainbow Effect

Many people believe that real diamonds do not produce rainbow colors. This is an inaccurate notion.

Real diamonds do create a rainbow effect (Fire), but it is moderate and balanced with white light.

On the other hand, Moissanite often produces a significantly stronger rainbow effect. If the stone constantly displays vibrant colored flashes under strong light, it could be a sign of Moissanite.

Method 3: Check the Quality of the Facet Cut

Diamonds are typically cut with very high precision.

When observed closely:

• Facet edges are sharp.
• Facet surfaces are symmetrical.
• Angles are clearly defined.

Many inexpensive simulants often have slightly rounded edges or lack sharpness.

Observe the quality of diamond facet cuts closely

Method 4: Check Surface Abrasion

Diamond is the hardest natural material on the Mohs scale, with a hardness of 10/10.

Therefore, diamonds that have been used for a long time usually retain sharpness at their facet edges.

In contrast, Cubic Zirconia or Topaz may show:

• Worn facet edges.
• Small scratches.
• Loss of luster over time.

Method 5: Observe Under a 10x Loupe

A 10x loupe is a basic tool in the gemological industry. Experts typically use it to examine:

• Inclusions.
• Natural fractures.
• Growth lines.
• Facet quality.
• Laser inscriptions on the girdle.

Natural diamonds often have unique formation characteristics within their crystal structure that simulants find difficult to replicate completely.

A 10x loupe is used to examine the natural characteristics of a diamond

Method 6: Test with a Thermal Conductivity Tester

Diamonds have very high thermal conductivity.

A thermal conductivity tester helps distinguish diamonds from:

• Cubic Zirconia (CZ)
• White Sapphire
• White Topaz
• Glass

However, this method may be confused with Moissanite if older equipment is used.

Method 7: Test with an Electrical Conductivity Tester

Moissanite has different electrical conductivity properties than most natural diamonds.

Therefore, devices that combine thermal and electrical conductivity measurements can now help distinguish diamonds from Moissanite more effectively.

Method 8: Check Diamond Certificates

A diamond with a certificate from reputable organizations like GIA, IGI, HRD makes it easy for buyers to verify its origin and quality.

Many diamonds are also laser-inscribed with a serial number on the girdle for direct comparison with the gemological institute's data.

This is one of the most reliable authentication methods available today.

Carefully check the GIA certificate of the diamond